(1) Field of Invention
This invention relates to containers for carrying and storing ice, drinks and food while enroute to or from picnics at the beach. More particularly it relates to coolers which can be propelled along a surface on rollers or wheels.
(2) Description of the Prior Art
Most conventional coolers do not have a means of locomotion but are carried to and from the picnic site by handles. Often the containers are heavy, cumbersome and and difficult to maintain on a level keel during the trip from the automobile to the picnic site.
Attempts to provide mobility to refrigerating units usually involved rollers or wheels. In 1967, Kritzer, Jr. (U.S. Pat. No. 3,308,633), discloses small wheels or rollers for transporting his Heating and Cooling System across a supporting surface in elevated relation to that surface.
Vega, in 1971, (U.S. Pat. No. 3,591,194) disclosed an ice chest cart with a plurality of compartments and a pair of wheels attached by an axle to the underside of the cart. The handle, similar to a lawn mower handle, was pivotally attached to a horizontal stub extending from the bottom of the cart midway between the ends.
Other art disclosed an attempt to combine a portable case with a collapsible trolley. Cassimally et al, in 1981, (U.S. Pat. No. 4,273,222) reveals a Combined Portable Case and Luggage Trolley which unfolds to provide a hand truck to carry other luggage. A pair of spring loaded wheels snap out of the bottom of the case to provide a rolling means. A rigid frame unfolds from the top surface of the case to provide a handle.
The most recent prior art discloses a Portable Wheeled Cooler Apparatus which combines the frame handle of Cassimally et al with the wheels of Vega. The refinement, disclosed in 1988 by Bartholomew et al (U.S. Pat. No. 4,724,681), is that the two wheels are mounted so that they do not extend beyond the perimeter of the container until the cooler is pitched forward during towing. The container is also tapered on the ends so that the wheels can be housed in wheel cutout sections for protection during storage.
Although track type treads are known in load carrying vehicles they are used in powered trucks or else used in hand trucks for purposes other than disclosed in the present invention.
Prior art known to this inventor includes the following U.S. Pat. Nos.:
______________________________________ 2,763,489 9/1956 Marsalis 2,827,972 3/1958 West 3,308,633 3/1967 Kritzer, Jr. 3,591,194 7/1971 Vega 4,273,222 6/1981 Cassimally et al 4,581,902 4/1986 Starck et al 4,724,681 2/1988 Bartholomew et al ______________________________________